<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>canvas练习</title>
		<link rel="stylesheet" href="css/reset.css" />
	</head>
	<body>
		<canvas id="canvas"></canvas>
		<div class="btn">
			<input id="random" type="button" value="random" />
			<input id="heart" type="button" value="heart" />
			<input id="circle" type="button" value="circle" />
			<input id="wave" type="button" value="wave" />
		</div>
		
		<script>
			window.onload = function(){
				canvas = document.getElementById("canvas");
				ctx = canvas.getContext("2d");
			}
		</script>
	</body>
</html>
